The use of in-floor and in-wall heating and cooling systems that operate based on the conduction and radiation forms of heat transfer is well known. Such systems are used, for example, as an alternative to forced air heating and cooling systems, which operate based on convective heat transfer. Primarily, in-floor and in-wall systems comprise a series of pipes that circulate heated water or resistive electric cable, mesh or film that generates heat when an electric current is applied thereto. In-floor radiant heating technology in particular is used commonly in homes and businesses today.
Electrical floor heating systems have very low installation costs and are well suited for kitchens, bathrooms or rooms that require additional heat, such as basements. One advantage of electric floor heating is the height of installation. For example, floor buildup can be as little as about one millimeter. Electric underfloor heating can also be quickly installed, in as little as half a day to a day depending on the size of the area to be heated. In addition, warm up times are generally decreased because the cables are installed proximate to the finished flooring, i.e. tile, where they can begin to heat the flooring immediately. In contrast, forced-air and water-based heating systems generate hot air or water in a single centralized location, and then direct the hot air or water to a location that needs to be heated, with attendant transmission losses and reduced efficiency. Electric systems are also offered in several different forms, such as those that utilize a long continuous length cable or those that employ a mat with embedded heating elements. In order to maximize heat transfer, a bronze screen or carbon film heating element may be also used. Carbon film systems are normally installed under the wire and onto a thin insulation underlay to reduce thermal loss to the sub floor. Vinyls, carpets and other soft floor finishes can be heated using carbon film elements or bronze screen elements.
Another type of in-floor heating system is based on the circulation of hot water, i.e., a “hydronic” system. In a hydronic system, warm water is circulated through pipes or tubes that are incorporated into the floor. Such systems generally use pipes from about 11/16 inch to 1 inch to circulate hot water from which the heat emanates. The size of the pipes or tubes generally translates into a thicker floor, which may be undesirable. One other disadvantage of hydronic systems is that a hot water storage tank must be maintained at all times, which is less efficient than an electric floor heating system.